Thermochemistry: an Ice Calorimeter Determination of Reaction Enthalpy

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Thermochemistry: An Ice Calorimeter Determination of
Reaction Enthalpy
INTRODUCTION
In CHM151 you learned about the first law of thermodynamics, the statement that energy may be transferred (as heat or work) between a system and the surroundings, but energy is neither created nor destroyed. This law is the foundation for calorimetry, the technique of measuring heat effects in the surroundings to gain insight into energy transfers to or from a system of interest.

In the typical calorimeter, we measure heat-induced temperature changes. In fact, heat is sometimes defined as the type of energy transfer caused by temperature differences between system and surroundings. In today’s lab, by contrast, the heat transfer takes place with no temperature change–it is an isothermal heat transfer. Consider the second law as you think about what drives this heat transfer.

PREPARING FOR THE EXPERIMENT
Background reading
Read and thoroughly understand this section of the lab manual and the Thermodynamics chapters in the lecture textbook.
Preparing the lab notebook
Write a brief outline of the planned experimental procedure in your notebook. Include the hazardous properties of all lab chemicals.
Leave space to record significant experimental details, such as the stock reagent concentrations (taken from the stock-bottle labels), descriptions of the instruments used, and the names of your coworkers. Prepare a table that will allow you to record the required data, including the pipet readings and ice-bath temperature readings as a function of time. Read the pipet to 0.001-mL precision, read the thermometer to 0.1 °C precision, and record time to the nearest second.

PROCEDURE
I.
Test the calorimeter apparatus set-up before running the experiment. A.
B.
C.
D.
E.
F.
Fill the beaker to the top with water. (Don’t use ice...
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